Draft gear for railway draft rigging



Aug. 5, 1958 r H. w. MULCAHY 2,846,083

DRAFT GEAR'FOR RAILWAY DRAFT RIGGING Filed Jan. 23. 1956 :s Sheets-Sheet 1 Inv-enZ or: mvz only.

H. W. MULCAHY DRAFT GEAR FOR RAILWAY DRAFT RIGGING Aug. 5, 1958 3 Sheets-Sheet 2 Filed Jan. '23, 1956 'lnvey or: u 4'653 lly Aug. 5, 1958 H. w. MULCAHY DRAFT GEAR FOR RAILWAY DRAFT RIGGING 5 Sheets-Sheet 5 Filed Jan. 23. 1936 llllllllnlk .lIlV-lli-IPII'IIIIIIII United 2,846,083 Patented Aug. 5, 1958 ice DRAFT GEAR FOR RAELWAY DRAFT RIGGING Harry W. Mulcahy, Chicago, lll., assignor to W. H. Miner, Inc., Chicago, lllL, a corporation of Delaware Application January 23, 1956, Serial No. 560,556

6 Claims. (Cl. 213-48) This invention relates to draft gear for railway draft rigging- It is a main object of the invention to provide a gear for the draft rigging of a caboose, which gear will fit in the standard pocket of the rigging, has long travel, low initial resistance, and gradual build-up of resistance during a major portion of travel of the gear, thereby to cushion shocks produced by run-in and run-out during operation of the train.

Another object of the invention is to provide a caboose gear which, in addition to low resistance cushioning during a major portion of the travel of the gear, also has rapid build-up of resistance during a final portion of that travel, thereby to protect the caboose during switching and pusher service.

Another object of the invention is to provide a caboose gear which has a gradual build-up of resistance through from 80% to 85% of its travel, followed by a more rapid build-up of resistance during the remainder of that travel.

Further objects of the invention not specifically mentioned here will be apaprent from the detailed description and claims which follow, reference being had to the accompanying drawings in which a prefererd embodiment of the invention is shown by way of example and in which:

Figure l is a front end elevational view of an assembled s Figure 2 is a front end elevational view of the gear casing;

Figure 3 is a cross sectional view along the line 33 of Figure 1, looking in the direction of the arrows and with the rubber units shown in full;

Figure 4 is a fragmentary cross sectional view taken along the line -i---;- of Figure 2, looking in the direction of the arrows;

Figure 5 is a side elevational view of the rear plunger;

Figure 6 is a front elevational view of the rear plunger;

Figure 7 is a front elevational view of the front follower;

Figure 8 is a fragmentary view of the gear, partly in section, showing the resilient units at the end of normal travel of the gear; and

Figure 9 is a view similar to Figure 8, showing the units at maximum travel of the gear.

The caboose gear of the present invention consists of a generally cylindrical casing A that is open at both ends and is closed at its rear end by a rear plunger B, and at the front by a front plunger C. Within the casing thus formed is a resilient column consisting of rubber pads D, which column is divided into groups or sections by aligning separators E, there being a front follower F interposed between the front resilient unit D and the front wall of the front plunger C.

The casing A has generally cylindrical walls It) which flare outwardly at four points 11, which wall portions 11 contain an inwardly opening groove 12 that is closed at the rear end of the casing by an end wall 13, and partially CHI closed at the front end of the casing by a wall portion 14.

At the front end of the casing is a laterally extending continuation 15 of the groove 12 and a forwardly extending continuation 16 of the continuation 15, which opens into the front end of the casing.

Fitted within the casing is a rear plunger B which is generally cup-shaped, having a rear wall 20 which contains in it sockets 21 by which the resilient units are maintained in alignment, as will presently appear. Extending forwardly from the rear wall 20 is a cylindrical wall 22. Projecting radially outwardly from the wall 22 are four lugs 23 which fit into the grooves 12, 15 and 16 of the casing, as will presently appear.

Each of the resilient members D is of known construction, consisting of a pair of circular metallic plates 25 between which is a solid mass of rubber 26 that is bonded to the plates. The edges of the rubber pad 26 are formed concavely, as indicated at 27, to provide space within the unit into which the rubber is displaced as the unit is compressed. Each unit D contains in one of its faces bosses 28 which are of spherical section, and in its other faces sockets 29, also of spherical section, for the purpose of maintaining the unit aligned in known manner.

Each of the separators E consists of a circular web 3%) from the edge of which a flange 31 extends, the flange being provided with outwardly extending lugs 31a that duplicate the lugs 23 on the rear plunger and fit in the grooves in the casing, as will presently appear. Projecting from one face of the web 30 are bosses 32, and sockets 33 are indented in the other face of the web in axial alignment with the bosses 32.

The front plunger C is similar to the rear plunger B, except that the front Wall 35 thereof contains a centrally located rectangular opening 36 and the wall 38 is longer than the wall 22. The front follower F consists of a disk 37 which fits Within the rearwardly extending wall 38 of the front follower, and a forwardly extending rectangular lug 39 which projects into the rectangular opening 36 in the front wall 35 of the plunger C. Sockets ll are recessed into the rear face of disk 37 to receive the bosses 28 of the adjacent unit D.

in assembling the gear, the casing A is positioned upon a suitable support with its rear end downward. Rear plunger B is telescoped into the casing with the lugs 23 thereon registering with the continuation 16 of the continuation 15. The plunger is telescoped into the casing until these lugs strike the rear wall of continuation 15, at which time the plunger is rotated to bring the lugs into registration with the groove 12 in the casing, the plunger then moving downwardly until the lugs 23 engage the rear wall 13 that defines the rear end of the groove 12.

The resilient units D and separators E are then inserted in the casing, the separators being inserted in the same manner as the rear plunger B, that is, the lugs 31a are registered with and passed through grooves 16, 15, and 12 in the same manner as lugs 23. When the last resilient unit D is in place, the front follower F is registered therewith and the front plunger C fitted over the column and front follower. Pressure is applied to the column through the lug 39 to compress it sufiiciently to permit the lugs on the front plunger C to travel through the continuations 16 and 15 into the groove 12, at which time the rectangular lug 39 will register with the rec tangular opening 36 in the front wall 35 of the plunger to maintain the column aligned. Pressure is then removed from the lug 39 allowing the column to expand and push the plunger C outwardly until the lugs thereon engage the wall portions 14 at the forward end of the groove 12.

During compression and expansion of the gear, the col umn is stabilized by the flanges on the plungers C and D and on the separators E. Lugs 23 and 31a, through their engagement with the grooves 12, prevent rotation of the plungers and followers around the axis of the column. Interengagement ofthe' bosses 28 and sockets 29 of the units D and interengagement of those bosses and sockets with the socket-sand bosses on the plungers and separators, fix the unitswith respect thereto'to complete the stabilization of the column.

As will be seen in Figure 3, the rear group ofpads in the gear shown by way of example consists of two pads in the group, and the group immediately forwardly thereof contains buta single pad.- The remaining two groups consist of two pads each. This particular arrangement is subject to modification within the teachings of the invention. It will also be'notedl' that the bosses 28 on the pads in the rear groups extend rearwardly and that thebosses in the pads at the front end of the column extend forwardly. This arrangement likewise may be varied within the teachings of the invention.

The gear shown by way of example, when assembled as above, is of such overall length as to enable it to-fit in the standard length pocket of a draft rigging. When used in connection with a long shank coupler, the gear has a maximum travel of six (6) inches. It has a low initial resistance in the range of 3,000 to 5,000 pounds, which resistanceincreases gradually to the range of 25,000 to 30,000 pounds during the first and major portion of the travel of the gear. In one instance, the gear must travel between 80% and 85% of its maximum travel before the resistance of the column builds up to the 25,000 to travel, it is still capable of further travel during which the resistance of the resilient column builds up more rapidly. As will be seen in Figure 9, when the gear has completed its maximum travel, the rubber 26 in the units D has been displaced beyond the edges of the plates 25 to which this rubber is bonded, into engagement with the flanges on the separators E. The rubber in the units within the front plunger C and rear plunger B will be similarly displaced into engagement withthe inner walls of these plungers. Through this arrangement, during the last 20% of travel of thegear, the resistance of the column is built up from the 25,000to 30,000 pound range to a range ofifrom 300,000 to 350,000 pounds.

During, the normal course of operation of the train, the caboose i s-cushioned from shocks produced by the normal'run-in and-run-out of the train. The long travel through thelow resistance portion of the gear is sufficient to affordcomplete protection-to the caboose and to provide a highly comfortable ride to trainmen under these conditions. It often happens that a locomotive willbe coupled to the rear end of the caboose and part or all of the train pulled by this locomotive. Under such circumstances, the forces which the draft gear must handle exceed the normal pressures and the gear travels into the latter portion of its travel in which resistance builds up rapidly to a value sufficient to'meet the conditions. The same action also results when a locomotive is coupled to the rear end of the caboose to aid movement of the train by pushing.

Having thus complied with the statutes and shown and described a preferred embodiment of my invention, what I consider new and-desire to have protected by Letters Patent'is pointed out in the appended claims.

What I claim is:

1. A draft gear for railway draft rigging, having long travel, low initial resistance with little increase in resistance during the major portion of that travel, followed by rapid increase in resistance during the remainder of that travel, comprising: a metallic casing of generally cylindrical cross section open at both ends; a plurality of longitudinal grooves opening into the interior of said casing and extending into proximity to both ends of the casing; a cup-shaped rear plunger telescoped into the rear end of the casing; lugs on the front end of saidplunger projecting radially outwardly therefrom into said grooves and engaging the ends" thereof to hold the plunger in the casing; a resilient column within the casing and rear plunger composed of a plurality of resilient units; separators dividing said column into sections; lugs on said separators projecting radially therefrom into said grooves; a cup-shaped front plunger telescoped into the front end of the casing into which plunger said resilient column extends; lugs' on therear end of said front plunger projecting radially therefrom into said grooves and engaging the ends thereof to hold the plunger in the casing, there being a rectangularsocket opening through the front wall of said front plunger; a front follower within the front plunger engaging the resilient column and plunger; and a rectangular boss on said front follower projecting into the socket in'the front plunger.

2. A draft gear as specified in claim 1, in which extensions of the grooves in the casing extend laterally from the frontends of the grooves thence longitudinally of the easing into the front end thereof,- through which extensions the lugs on the plungers and separators are passed into the longitudinal grooves as the gear is assembled.

3. A draft gear as specified in claim 1, in which each resilient unit consists of a pair of circular metal plates between which a solid body of rubber is disposed and bonded to the plates, which body of rubber has edge configuration essentially parabolic in cross section pro viding space within the edges of the plates into which the rubber is displaced during compression of the unit,

to completely fill that space at the completion of the major portion of the travel of the gear.

4. A draft gear as specified in claim 3, in which the spaces at the edges of the rubber units are completely filled when the gear has completed between and of its maximum travel. v

5. A draft gear as specified in claim 3, in which the separators comprise circular plates disposed between adjacent resilient units, and flanges 0n the edges of the plates engage the casing walls "to stabilize the column.

and in which the lugs on the separators project beyondthe flanges into the grooves to prevent rotation of the separators around the axis of the column while permitting the separators to move axially in the casing.

6. A draft gear as specified in claim 5, in which the rubber in the resilient column units is displaced beyond the metal plates of the units outwardly into engagement with the flanges during the final 15% to 20% of the travel of the gear.

References'Cited in the file of this patent UNITED STATES PATENTS 971,415 Spencer Sept. 27, 1910 2,417,154 Dath Mar. 11, 1947 2,540,334 Johnson Feb. 6, 1951 2,551,064 Spenner May l-,- 1951 FOREIGN PATENTS 672,646 Germany Mar. 7, 1939 

